The invention relates to a device and a process for cooling liquids containing solids by expansion with the aid of a cyclone, the vapours which form being free of droplets and solids particles.
A particular embodiment of the process according to the invention relates to a process for cooling waste water containing solids particles, which forms in the production of propylene oxide according to the propylene chlorohydrin process, hereafter called "saponifier effluent".
The known processes for cooling liquids containing solids by means of heat exchangers prove unsuitable, since the solids contained in the liquid to be cooled are deposited on the surfaces of the heat exchangers, thus causing a reduction in thermal conductivity and uneconomic cleaning costs and stoppages.
Furthermore, the processes known per se for the flash evaporation of liquids with the aid of cyclone-like containers for cooling liquids containing solids also prove unsuitable, since the special flow properties of a liquid containing vapour bubbles leads to atomization at the entrance and on the walls of apparatus of conventional design. Since the drops contain solids particles, hard deposits which are very difficult to remove, form on unrinsed areas (e.g. on the cover, in the vapour discharge pipe, or in the heat exchangers installed for recovering heat).